BMW M4 Convertible (2018) Wheel Fitment
BMW M4 Convertible (2018): 5x120 bolt pattern, 72.6mm center bore. Factory wheels: F: 19x9.0J R: 19x10.0J. Reference fitment ranges.
Wheel Size & Offset at a Glance
| Configuration | Wheel Size & Offset |
|---|---|
| Factory (OE) | F: 19x9.0J R: 19x10.0J |
| Flush Fitment | F 20x9.5J ET20 / R 20x10.5J ET35 |
| Maximum Aggressive | F 20x10.0J ET15 / R 20x11.0J ET30 |
How to Read Wheel Offset & Measurements
Use these two references before ordering: the left diagram shows where each spec (PCD, center bore, offset, width and diameter) is measured on the wheel; the right diagram shows how positive, zero and negative offset shift the wheel face relative to the hub centerline.
BMW M4 Convertible OE Wheel Specs
The 2018 BMW M4 Convertible (Convertible) uses a 5x120 bolt pattern with a 72.6mm center bore. Factory wheels are F: 19x9.0J R: 19x10.0J.
Why the factory spec works for most owners:
- Matches the chassis tuning used to help offset reduced structural rigidity
- Balances ride comfort with the sportier character typical of this body style
- Keeps unsprung weight low for stable handling
- Maintains clearance for the factory brake package and suspension components
Flush Fitment
For a flush look with minimal rubbing, F 20x9.5J ET20 / R 20x10.5J ET35 is the recommended starting point on a stock or mildly lowered BMW M4 Convertible.
Maximum Aggressive Fitment
F 20x10.0J ET15 / R 20x11.0J ET30 is a more aggressive reference setup. Beyond this, expect rubbing under compression without fender rolling or camber correction.
5-Tier Configuration Options
A Flush Fit (Conservative) F 20x9.5J ET20 / R 20x10.5J ET35
Recommended setup: F 20x9.5J ET20 / R 20x10.5J ET35 | Economy impact: Negligible | Best for: Daily commuting, family use
Appearance: 7/10 | Comfort: 9.5/10 | Install difficulty: ★☆☆☆☆
Estimated cost: $450-800 (wheels + tires + install)
B Comfortable Upgrade F 20x9.5J ET19 / R 20x10.5J ET34
Recommended setup: F 20x9.5J ET19 / R 20x10.5J ET34 | Economy impact: -2 to -4% | Best for: Daily / street
Appearance: 8/10 | Comfort: 9/10 | Install difficulty: ★☆☆☆☆
Estimated cost: $1,950-2,550 (wheels + tires + install)
C Balanced F 20x10.0J ET18 / R 20x11.0J ET33
Recommended setup: F 20x10.0J ET18 / R 20x11.0J ET33 | Economy impact: -4 to -6% | Best for: Street
Appearance: 8.5/10 | Comfort: 8/10 | Install difficulty: ★★☆☆☆
Estimated cost: $2,600-3,400 (wheels + tires + install)
D Aggressive F 20x10.0J ET16 / R 20x11.0J ET31
Recommended setup: F 20x10.0J ET16 / R 20x11.0J ET31 | Economy impact: -6 to -9% | Best for: Show / occasional track
Appearance: 9/10 | Comfort: 6.5/10 | Install difficulty: ★★★☆☆
Estimated cost: $3,900-5,000 (wheels + tires + install)
E Max Aggressive F 20x10.0J ET15 / R 20x11.0J ET30
Recommended setup: F 20x10.0J ET15 / R 20x11.0J ET30 | Economy impact: -8 to -12% | Best for: Show only
Appearance: 9.5/10 | Comfort: 4/10 | Install difficulty: ★★★★☆
Estimated cost: $4,800-6,200+ (wheels + tires + install)
Performance Comparison Matrix
| Metric | Tier A | Tier B | Tier C | Tier D | Tier E |
|---|---|---|---|---|---|
| Wheel Spec | F 20x9.5J ET20 / R 20x10.5J ET35 | F 20x9.5J ET19 / R 20x10.5J ET34 | F 20x10.0J ET18 / R 20x11.0J ET33 | F 20x10.0J ET16 / R 20x11.0J ET31 | F 20x10.0J ET15 / R 20x11.0J ET30 |
| Economy Impact | Negligible | -2 to -4% | -4 to -6% | -6 to -9% | -8 to -12% |
| Appearance | 7/10 | 8/10 | 8.5/10 | 9/10 | 9.5/10 |
| Comfort | 9.5/10 | 9/10 | 8/10 | 6.5/10 | 4/10 |
| Install Difficulty | ★☆☆☆☆ | ★☆☆☆☆ | ★★☆☆☆ | ★★★☆☆ | ★★★★☆ |
| Cost Range | $450-800 | $1,950-2,550 | $2,600-3,400 | $3,900-5,000 | $4,800-6,200+ |
| Best For | Daily commuting, family use | Daily / street | Street | Show / occasional track | Show only |
Real-World Reference Cases
The examples below are compiled from typical ANKUSI customer configurations and are labeled as reference cases, not individually verified real-world builds.
Case 1: Daily Driver (Flush Fit (Conservative))
Profile: Everyday driving, prioritizes comfort and low running cost.
Setup: F 20x9.5J ET20 / R 20x10.5J ET35
Cost: ~$620
Outcome: Minimal visual change, ride and fuel economy essentially unaffected.
Case 2: Balanced Enthusiast (Balanced)
Profile: Wants a sportier stance without sacrificing daily usability.
Setup: F 20x10.0J ET18 / R 20x11.0J ET33
Cost: ~$3,000
Outcome: Noticeable visual upgrade, fuel economy drop within the expected range.
Case 3: Show Build (Max Aggressive)
Profile: Built primarily for shows or occasional track/show use.
Setup: F 20x10.0J ET15 / R 20x11.0J ET30
Cost: ~$5,500
Outcome: Maximum visual impact; daily comfort and fuel economy are heavily compromised, physical test fit required before production.
Decision Guide
Offset & Backspacing Reference
Backspacing is calculated as wheel width (in) ÷ 2 + offset (mm) ÷ 25.4 + 0.5 (flange allowance):
- Flush: F 20x9.5J ET20 → ~6.04″ F backspacing, R 20x10.5J ET35 → ~7.13″ R backspacing
- Max: F 20x10J ET15 → ~6.09″ F backspacing, R 20x11J ET30 → ~7.18″ R backspacing
Want to check a different width or offset before you order? Use our Offset & Backspacing Calculator to solve the numbers yourself, or looking for your exact BMW spec, or want a wheel built to a custom offset for your BMW M4 Convertible? Contact ANKUSI with your bolt pattern and offset target and we will confirm the correct forged wheel spec for your build.